Absorbance amplification using chromophore-nanoplasmon coupling for ultrasensitive protein quantification

Area of Science:

• Nanotechnology
• Biochemistry
• Spectroscopy

Background:

• Commercial colorimetric biochemical assays often require high sensitivity for accurate quantification.
• Plasmonic nanostructures offer potential for enhancing optical properties of assays through near-field interactions.

Purpose of the Study:

• To investigate the use of plasmonic nanoscale Lycurgus cup arrays (nanoLCAs) for enhancing the sensitivity of commercial colorimetric biochemical assays.
• To evaluate the performance of nanoLCAs in a standard protein quantification assay, specifically the Bradford assay.

Main Methods:

• A 96-microwell plate was modified by integrating plasmonic nanoLCAs at the bottom of each well.
• The modified microplate was used with a commercial Bradford protein quantification assay to measure protein concentration.
• Absorbance values were measured at the plasmonic resonance wavelength to assess the enhancement effect.

Main Results:

• The plasmonic nanoLCA enhanced assay sensitivity by over two orders of magnitude (200-fold).
• A 5.1-fold reduction in sample volume was achieved while maintaining enhanced sensitivity.
• The near-field plasmonic energy coupling between nanoLCAs and assay chromophores increased absorbance values.

Conclusions:

• Plasmonic nanoLCAs provide a significant sensitivity enhancement for colorimetric biochemical assays.
• The nanoLCA-microplate platform is scalable to higher density formats (384- and 1536-well plates), enabling reduced sample volumes and increased throughput.
• This technology offers a promising approach for developing more sensitive and efficient diagnostic and analytical tools.